Straight hollow fiber filtration devices are ubiquitous. However, coiled hollow fiber modules were only recently disclosed. See U.S. Pat. No. 5,626,758. Indeed, multi-layered coiled hollow fiber devices were only briefly discussed in U.S. Pat. No. 5,626,758, with no mention of how to assemble or pot the fiber bundles. Devices containing coiled hollow fibers if designed properly are capable of inducing Dean vortices in their inner diameter or lumen. These vortices cause a sweeping of the inner lumen surface disrupting the boundary layer which forms there between the particles or dissolved species which are to be retained inside the fiber and materials and fluids which are to pass through the fibers to the outside of the fibers, thus causing depolarization and defouling of the fiber membrane creating greater efficiency in the filtration process.
In the prior art, epoxy is typically used to pot or bond one or both of the ends of straight hollow fibers together. Such fibers are potted by injecting epoxy around the outer layer of fibers. In this way, the outer surfaces of the ends of the fibers are formed into a liquid tight seal such that all fluid must pass through the lumen of the fibers in those areas that are potted. While this method is appropriate for straight hollow fibers, it has proven inadequate for the coiled hollow fiber devices, especially the multilayered coiled hollow fiber devices produced by the inventor's colleagues. See PCT/U.S.99/30141, filed Dec. 17, 1999.
As a mandrel is preferably-used to produce these the multi-layered coiled hollow fiber devices, the mandrel interfered with the potting. With the prior art method of injecting the epoxy from the outside inward, the epoxy does not seal around all of the fibers, especially the fibers positioned at or near the mandrel. The tightly wound, multiple layers of fibers formed a barrier to the epoxy penetrating the inner layers of fibers. Since the fibers did not pot properly, the performance of the module does not match the performance outputs predicted by the algorithms.